The protective toenail caps, covers, or nail polymeric sheaths, previously disclosed in U.S. Pat. No. 4,962,731, are very small polymeric caps configured to the general shape of an animal's toenail, particularly those of cats and dogs. The flexibility and resilience of the cap's construction material is such that deformation of the cap upon application to the animal's toenail provides a snug fit within limited ranges. It has been found that the most economical and applicable process and material for this application is a vinyl dip molding process developed especially for this process. Although other molding processes such as injection molding, blow molding, etc. were investigated, none proved to be as effective or as economical.
Over time, attempts to improve the durability of the cap have not been very successful as a result of an inability to increase durometer without sacrificing the deforming and resilience capability, thus making the cap harder to fit a variety of toenail sizes.
In addition, use of an adhesive to secure the caps in place on the toenail has been a problem since inception. A method had to be conceived for inducing a fast bonding adhesive into the very narrow opening in the cap at the time of its application to the animal. This was achieved by developing a formulation of cyanoacrylate with a density that allowed the adhesive to flow into the narrow opening through a special flexible funnel fitted to the nozzle of a small adhesive container. Although frequent overflows occur due to inexperienced technicians, this method of adhesive insertion into caps seems to be the most effective method to date. There is also the problem of premature adhesive curing in the containers before use and problems associated with nail cap removal from the animal's toe nail in some cases.
Various methods for controlling adhesive insertion and reducing the time required installing the cap on the animal's toenail have been researched. However, the manufacturing process as discussed above prevents the insertion of a cyanoacrylate adhesive, in its current state of development, during the manufacturing process. All attempts to inject the nail caps with this type of adhesive failed due to pre-curing of the adhesive due to heat associated with the molding process. In addition, several attempts to inject the nail caps after removal from the dip molding process proved to be labor intensive, thus making the process economically prohibitive. Attempts to insert a frangible bead into the caps failed for the same reasons. Manually handling the caps one at a time is too expensive and robotic insertion also proved to be cost prohibitive.
At least one attempt has been made by others to solve the adhesion problem as disclosed by Gat in U.S. Pat. No. 6,659,047. Gat suggested that the adhesive be inserted during the manufacturing process by either injection, insertion of a breakable bead, or by fusing two separate component parts, one of which is designed to contain the adhesive. Gat fails to exhibit a firm grasp of the problems involved in the manufacturing process. Due to the very small size of the cap, it is virtually impossible to perform the sequence suggested by Gat in any reasonably economical manner. Therefore, the search for an improved bonding method continues.
Continuing research efforts have shown promise with regard to the durability of the caps, especially where the caps are applied to dogs. Unlike cat nail caps, dog nail caps remain on the dog's toenail two to three times longer than on cat's toenails. This is due to the sloughing effect of the cat's toenail. As a result of such long duration, dogs generally wear the tips off the cap long before the nail configuration changes sufficiently to loosen the nail cap.
Therefore, a need exists for an improved animal nail cap having better durability, especially for dogs and heavier animals that tend to walk on rough surfaces, and the continuing need to solve the adhesion problems discussed above.